server.savebackupcount (Rust server ConVar)

server.savebackupcount is how many older copies of the world save Rust keeps next to the current one. The server's help text (marked "Generated" by Facepunch):

Number of rolling save-file backups to keep; each autosave rotates the oldest backup out

On build 25582902 the value was 2.

What it does on disk

Every save shifts the older copies down one place. With the default, the identity folder holds the current save and two older ones. On our test server, with server.saveinterval 600, they were ten minutes apart:

proceduralmap.4000.1420068679.289.sav      current
proceduralmap.4000.1420068679.289.sav.1    one save ago
proceduralmap.4000.1420068679.289.sav.2    two saves ago

In the game code the server uses the larger of server.savebackupcount and 2. Setting 0 or 1 does not remove .sav.1 and .sav.2. A higher value should keep that many older copies, each a full save file; we have only observed the default of 2.

They are not a backup

• The server never loads them. It only opens the plain .sav. If that file is missing or you delete it, the server generates a fresh map and ignores the copies beside it. Using one means stopping the server and putting it in place of the .sav yourself.
• They only go back a few saves. With 2 copies and a 10 minute interval you can go back 20 minutes, not to yesterday.
• They live on the same disk. A lost disk or a deleted folder takes them with it.
• They outlive a wipe that keeps the seed. If a wipe deletes only *.sav, last wipe's .sav.1 sits under the new world's name until the new map has saved twice. Delete *.sav.* too, as the wipe guide describes.

For copies you can restore after a real problem, take archives of the identity folder and keep them off the host.

Setting it

server.savebackupcount 2

In the game code the count is read when each save shifts the copies, so a change should apply from the next save without a restart. We have not tested a change on the test server. This ConVar is one that server.writecfg saves to serverauto.cfg: our test server had a server.savebackupcount "2" line there that neither server.cfg nor the command line set. server.readcfg runs serverauto.cfg first and server.cfg second, so a line in server.cfg wins.

In Panelra

Panelra's map wipe deletes the .sav.N copies along with the save. For real backups, Panelra takes scheduled archives of the server folder and stores them off the host.